<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 100px;
            height: 100px;
            background: red;
            position: relative;
            left: 0px;
            transition: 1s;
        }

        .lili {
            width: 100px;
            height: 100px;
            background: pink;
            position: relative;
            left: 0px;
            transition: 1s;
        }
    </style>
</head>

<body>
    <div class="box"></div>
    <div class="lili"></div>
</body>
<script>
    let box = document.querySelector('.box');
    let lili = document.querySelector('.lili');
    var obj = {
        fn: function () {
            console.log(this);
        }
    }
    obj.fn.call(box);   //box   若fn是箭头函数，则指向window
    obj.fn.apply(box);   //box   若fn是箭头函数，则指向window   传参是一个数组
    obj.fn.bind(box)();   //box   若fn是箭头函数，则指向window  

    /*
        call(this,a,b,c)
        apply(this,[a,b,c])
        bind(this,a,b,c)()
    */
</script>

</html>